/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing.google;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Multiset;
import com.google.common.collect.Multiset.Entry;
import com.google.common.collect.Multisets;
import com.google.common.collect.testing.AbstractCollectionTestSuiteBuilder;
import com.google.common.collect.testing.AbstractTester;
import com.google.common.collect.testing.FeatureSpecificTestSuiteBuilder;
import com.google.common.collect.testing.Helpers;
import com.google.common.collect.testing.OneSizeTestContainerGenerator;
import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.SetTestSuiteBuilder;
import com.google.common.collect.testing.TestSetGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.Feature;
import com.google.common.collect.testing.testers.CollectionSerializationEqualTester;
import com.google.common.testing.SerializableTester;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a {@code Multiset}
 * implementation.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtIncompatible
public class MultisetTestSuiteBuilder<E>
        extends AbstractCollectionTestSuiteBuilder<MultisetTestSuiteBuilder<E>, E>
{
    public static <E> MultisetTestSuiteBuilder<E> using(TestMultisetGenerator<E> generator)
    {
        return new MultisetTestSuiteBuilder<E>().usingGenerator(generator);
    }

    public enum NoRecurse implements Feature<Void>
    {
        NO_ENTRY_SET;

        @Override
        public Set<Feature<? super Void>> getImpliedFeatures()
        {
            return Collections.emptySet();
        }
    }

    @Override
    protected List<Class<? extends AbstractTester>> getTesters()
    {
        List<Class<? extends AbstractTester>> testers = Helpers.copyToList(super.getTesters());
        testers.add(CollectionSerializationEqualTester.class);
        testers.add(MultisetAddTester.class);
        testers.add(MultisetContainsTester.class);
        testers.add(MultisetCountTester.class);
        testers.add(MultisetElementSetTester.class);
        testers.add(MultisetEqualsTester.class);
        testers.add(MultisetReadsTester.class);
        testers.add(MultisetSetCountConditionallyTester.class);
        testers.add(MultisetSetCountUnconditionallyTester.class);
        testers.add(MultisetRemoveTester.class);
        testers.add(MultisetEntrySetTester.class);
        testers.add(MultisetIteratorTester.class);
        testers.add(MultisetSerializationTester.class);
        return testers;
    }

    private static Set<Feature<?>> computeEntrySetFeatures(Set<Feature<?>> features)
    {
        Set<Feature<?>> derivedFeatures = new HashSet<>(features);
        derivedFeatures.remove(CollectionFeature.GENERAL_PURPOSE);
        derivedFeatures.remove(CollectionFeature.SUPPORTS_ADD);
        derivedFeatures.remove(CollectionFeature.ALLOWS_NULL_VALUES);
        derivedFeatures.add(CollectionFeature.REJECTS_DUPLICATES_AT_CREATION);
        if (!derivedFeatures.remove(CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS))
        {
            derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
        }
        return derivedFeatures;
    }

    static Set<Feature<?>> computeElementSetFeatures(Set<Feature<?>> features)
    {
        Set<Feature<?>> derivedFeatures = new HashSet<>(features);
        derivedFeatures.remove(CollectionFeature.GENERAL_PURPOSE);
        derivedFeatures.remove(CollectionFeature.SUPPORTS_ADD);
        if (!derivedFeatures.remove(CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS))
        {
            derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
        }
        return derivedFeatures;
    }

    private static Set<Feature<?>> computeReserializedMultisetFeatures(Set<Feature<?>> features)
    {
        Set<Feature<?>> derivedFeatures = new HashSet<>(features);
        derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
        derivedFeatures.remove(CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS);
        return derivedFeatures;
    }

    @Override
    protected List<TestSuite> createDerivedSuites(
            FeatureSpecificTestSuiteBuilder<?, ? extends OneSizeTestContainerGenerator<Collection<E>, E>>
                    parentBuilder)
    {
        List<TestSuite> derivedSuites = new ArrayList<>(super.createDerivedSuites(parentBuilder));

        derivedSuites.add(createElementSetTestSuite(parentBuilder));

        if (!parentBuilder.getFeatures().contains(NoRecurse.NO_ENTRY_SET))
        {
            derivedSuites.add(
                    SetTestSuiteBuilder.using(new EntrySetGenerator<E>(parentBuilder.getSubjectGenerator()))
                            .named(getName() + ".entrySet")
                            .withFeatures(computeEntrySetFeatures(parentBuilder.getFeatures()))
                            .suppressing(parentBuilder.getSuppressedTests())
                            .withSetUp(parentBuilder.getSetUp())
                            .withTearDown(parentBuilder.getTearDown())
                            .createTestSuite());
        }

        if (parentBuilder.getFeatures().contains(CollectionFeature.SERIALIZABLE))
        {
            derivedSuites.add(
                    MultisetTestSuiteBuilder.using(
                                    new ReserializedMultisetGenerator<E>(parentBuilder.getSubjectGenerator()))
                            .named(getName() + " reserialized")
                            .withFeatures(computeReserializedMultisetFeatures(parentBuilder.getFeatures()))
                            .suppressing(parentBuilder.getSuppressedTests())
                            .withSetUp(parentBuilder.getSetUp())
                            .withTearDown(parentBuilder.getTearDown())
                            .createTestSuite());
        }
        return derivedSuites;
    }

    TestSuite createElementSetTestSuite(
            FeatureSpecificTestSuiteBuilder<?, ? extends OneSizeTestContainerGenerator<Collection<E>, E>>
                    parentBuilder)
    {
        return SetTestSuiteBuilder.using(
                        new ElementSetGenerator<E>(parentBuilder.getSubjectGenerator()))
                .named(getName() + ".elementSet")
                .withFeatures(computeElementSetFeatures(parentBuilder.getFeatures()))
                .suppressing(parentBuilder.getSuppressedTests())
                .withSetUp(parentBuilder.getSetUp())
                .withTearDown(parentBuilder.getTearDown())
                .createTestSuite();
    }

    static class ElementSetGenerator<E> implements TestSetGenerator<E>
    {
        final OneSizeTestContainerGenerator<Collection<E>, E> gen;

        ElementSetGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen)
        {
            this.gen = gen;
        }

        @Override
        public SampleElements<E> samples()
        {
            return gen.samples();
        }

        @Override
        public Set<E> create(Object... elements)
        {
            Object[] duplicated = new Object[elements.length * 2];
            for (int i = 0; i < elements.length; i++)
            {
                duplicated[i] = elements[i];
                duplicated[i + elements.length] = elements[i];
            }
            return ((Multiset<E>) gen.create(duplicated)).elementSet();
        }

        @Override
        public E[] createArray(int length)
        {
            return gen.createArray(length);
        }

        @Override
        public Iterable<E> order(List<E> insertionOrder)
        {
            return gen.order(new ArrayList<E>(new LinkedHashSet<E>(insertionOrder)));
        }
    }

    static class EntrySetGenerator<E> implements TestSetGenerator<Multiset.Entry<E>>
    {
        final OneSizeTestContainerGenerator<Collection<E>, E> gen;

        private EntrySetGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen)
        {
            this.gen = gen;
        }

        @Override
        public SampleElements<Multiset.Entry<E>> samples()
        {
            SampleElements<E> samples = gen.samples();
            return new SampleElements<>(
                    Multisets.immutableEntry(samples.e0(), 3),
                    Multisets.immutableEntry(samples.e1(), 4),
                    Multisets.immutableEntry(samples.e2(), 1),
                    Multisets.immutableEntry(samples.e3(), 5),
                    Multisets.immutableEntry(samples.e4(), 2));
        }

        @Override
        public Set<Multiset.Entry<E>> create(Object... entries)
        {
            List<Object> contents = new ArrayList<>();
            Set<E> elements = new HashSet<>();
            for (Object o : entries)
            {
                @SuppressWarnings("unchecked")
                Multiset.Entry<E> entry = (Entry<E>) o;
                checkArgument(
                        elements.add(entry.getElement()), "Duplicate keys not allowed in EntrySetGenerator");
                for (int i = 0; i < entry.getCount(); i++)
                {
                    contents.add(entry.getElement());
                }
            }
            return ((Multiset<E>) gen.create(contents.toArray())).entrySet();
        }

        @SuppressWarnings("unchecked")
        @Override
        public Multiset.Entry<E>[] createArray(int length)
        {
            return new Multiset.Entry[length];
        }

        @Override
        public Iterable<Entry<E>> order(List<Entry<E>> insertionOrder)
        {
            // We mimic the order from gen.
            Map<E, Entry<E>> map = new LinkedHashMap<>();
            for (Entry<E> entry : insertionOrder)
            {
                map.put(entry.getElement(), entry);
            }

            Set<E> seen = new HashSet<>();
            List<Entry<E>> order = new ArrayList<>();
            for (E e : gen.order(new ArrayList<E>(map.keySet())))
            {
                if (seen.add(e))
                {
                    order.add(map.get(e));
                }
            }
            return order;
        }
    }

    static class ReserializedMultisetGenerator<E> implements TestMultisetGenerator<E>
    {
        final OneSizeTestContainerGenerator<Collection<E>, E> gen;

        private ReserializedMultisetGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen)
        {
            this.gen = gen;
        }

        @Override
        public SampleElements<E> samples()
        {
            return gen.samples();
        }

        @Override
        public Multiset<E> create(Object... elements)
        {
            return (Multiset<E>) SerializableTester.reserialize(gen.create(elements));
        }

        @Override
        public E[] createArray(int length)
        {
            return gen.createArray(length);
        }

        @Override
        public Iterable<E> order(List<E> insertionOrder)
        {
            return gen.order(insertionOrder);
        }
    }
}
